I have collected some data on all older Brno and CZ rifles.
I have a copy of the poster you are referring to as well as old Shop manuals and parts lists for a lot of the sporting guns.
The history is patchy in that I have had to rely on heresay from many authors and lots of gaps need to be filled.
To give you an example of what I have on the ZG 47 or as it is more correctly named the Galas rifle:
THE GALAS RIFLE: ZG 47:
This rifle is viewed by many as the pinnacle in Mauser action development and represents arguably of the finest factory production rifles ever made.
The ZG47 unfortunately is relatively rare and short lived, in that production only saw 20,000 rifles made.
The heart of the Galas rifle lies in the modified standard length Mauser 98 action with solid left sidewall and double squared action bridges. The originator of this rifle was the engineer Otakar Galas of Zbrojovka Brno and is designated by the model number ZG 47 indicating design in 1947.
The rifle with SN 00001 with date stamp 50 (1950) was made in cal 9.3x62 Mauser and belonged to the late Tony Harrison of Cape Town South Africa. It was originally imported by Bren Arms formerly of Cape Town in the RSA. The rifle is currently in possession of Mark Harrison, son of the late Mr. Harrison Snr.
The rifle itself is in pristine condition and I have had the pleasure to actually handle and photograph it
Although early advertisements claimed that the ZG47 was only made in 8 calibers it would appear that other rare and unreported calibers were found in this rifle.
Rifle ZG 47 with SN 05217 dated 1956 was made in cal 8x68S and a rare 9.3x64 Brennecke SN 02862 with barrel date stamp 65 and action stamp 57 is noted.
ZG 47 rifle configurations:
There is a paucity in the gun literature regarding the specifications on the Galas rifle and specifically regarding origins.
The following variations are noted from early factory parts catalogs on the ZG 47 rifle.
The basic barrel length on the ZG 47 was given as a 60 cm / 4 groove barrel in two weight configurations.
1.        HEAVY BARREL: 7X57, 7X64, 8X57JS, 8X60, 8X64S, 30-06, 270WIN, 9.3X62
2. LIGHT BARREL: 7X57, 7X64, 8X57JS, 8X60, 30-06, 270WIN
1.        Standard Stock: In 3 configuartions: BASIC, RELIEVED and LIGHT
2.        Deluxe A: also in BASIC, RELIEVED and LIGHT (No schnabel but with a rounded black tip and Monte Carlo cheekpiece)
3.        Deluxe B: Schnable fore end in Basic, Relieved, and light configuration.
4.        Deluxe C: Slender stock
5.        Mannlicher Stock: Optional
6.        Super deluxe:
The ZG 47 was offered in the following standard caliber choices:
7x57 Mauser, 8x57S, 8x60S, 8x64S, 30-06, 270 Win and 9.3x62 Mauser.
Special order rifles could be had in 10,75x68 and 5.6x61 Vom Hofe.
ZB also offered as special order any Rimless cartridge no longer than 3. 33 inches or 85mm thus rare rifles have known to exist in calibers such as the 9.3x64 Brenneke and the 8x68S.
The factory poster for the ZG 47 rifle recommends the 8x64S caliber as the universal caliber for all hunting.
Apart from the sporting configurations two sniper rifles were also made. The ZG47 SN as well as a ZG 51 SN.
The ZG 51 was originally submitted by Galas with the ZG47 action but the then russian influence desigantated that the rifle be built on a Mannlicher 1891 / 30 action. The ZG51 production was very limited and was replaced by the Vz 54 built between 1954 and 1957. This too was built on the Mannlicher 1891/30 action.
These were built in cal 7.92x64 and a single shot target rifle ZG 474 in cal 7.92x57 is also noted in the literature.
The ZG 47 like its predecessors sported the doubled square bridge action with integral dove tail grooves for scope mounting. This feature was part of the latter 721 and 722 models ( post serial number 23,000 ), the ZG 47 series, the later Koucky brothers series ZKK as well as the current CZ range of sporting rifles.
The origin of this mounting system is not known to me but I summize it may be a Galas design as it's use falls within his tenure at ZB
The original BRNO scope mount for the ZG 47 utilized as one piece mounting system used to mount the Meopta scopes made in Czechoslovakia
Who was Otakar Galas: ( Otagar ?)
Born 1904 Syrovice in former Bohemia
Graduates from State technical college in 1927.
Joins Ceskoslovenska Zbrojovka Brno after graduation.
After the occupation of the Sudetenland in 1938 and subsequent take over of the rest of Czechoslovakia Galas flees to the UK in 1940.
Although he is not part of the design team of the BREN gun he also works at BSA on it's production in the UK. Also accredited with work on the Oerlikon anti-aircraft gun system and the BESA machinegun.
At the conclusion of the war Galas returns to Czechoslvakia in 1945 where he is responsible for the design of the ZG 47 and its derivatives.